Effect of high CuO additive on the properties of Nickel-zinc ferrite for near field communication

In this work, Nickel-zinc ferrite materials with 6 %～10 % high CuO mass content were prepared below 961 °C by a traditional metal oxide ceramic sintering process, which includes powder mixing, presintering, ball-milling, granulation and sintering. The effect of high CuO mass content on the electromagnetic properties of Nickel-zinc ferrite was studied. The results show that all the samples present a spinel structure without impurities. With the increase of CuO content from 6 % to 10 %, the hysteresis loops change visibly in wideness and height, in which B_s (Saturation magnetic induction) = 350 ∼ 400mT, B_r(Remanent magnetic induction) = 240 ∼ 300mT, H_c (Coercivity) = 110 ∼ 200 A/m and the shrinkage of the sintered sample increases from 113.9 % to 115.8 %, the density boosts from 4.81 g/cm ³ to 5.05 g/cm ³ and T_c (Curie temperature) increases from 175 °C to 260 °C. The impedance of the sample at low frequency has no obvious relationship with the CuO mass content, but the impedance of Nickel-zinc ferrite with high CuO content is about 65 Ω bigger than that of the samples with low CuO content when the frequency is above 500 MHz. P_cv(Core loss) reaches the highest value when the CuO mass content is 9 %. For the sample with 8 % CuO, the magnetic loss is minimum and the cut-off frequency is maximum, being 5.7 and 20.56 MHz, respectively.